1. Field of the Invention
The present invention relates to a camera for use with photo film coated with a magnetic recording layer. More particularly, the present invention relates to an improvement in which a magnetic head in a camera reliably can contact a magnetic recording layer.
2. Description of the Related Art
A camera for use with photo film coated with a magnetic recording layer is disclosed, for example, in International Publications WO 90/04201 and 90/04202. The camera reads data from, and writes data to, the magnetic recording layer during movement of the film. A magnetic head, which is disposed on a film path defined in the camera, is used. Examples of magnetic data stored before photography are the type and sensitivity of the film. Magnetic data written to the recording layer during photography can be various photographing data which is related to conditions of photography.
The photo film includes a film base which is about 120 microns thick, i.e., two or three times as thick as ordinary magnetic tape such as audio tape. The photo film thus has a higher rigidity than audio tape. There is a proposed improvement in JP-A (Japanese Patent Laid-open Publication No.) 4-11237, in which a pad is disposed to confront a magnetic head in swingable fashion in a longitudinal direction of the film, and has curvature away from the magnetic head. The use of this pad enables the contact between the film and the magnetic head to be better, because the pad can swing to compensate an inclination in the position of the magnetic as mounted.
In writing data magnetically to the film, it is preferable to use portions on the film near either longitudinal edge outside of imaging frames, because the film must be rubbed by the magnetic head. However, sometimes the longitudinal edges have a roughly slitted portion, because the strips of the photo film are produced from a wide web material of the photo film, which are slitted longitudinally by a slitting apparatus in a factory. When the roughly slitted portion of the film in the camera is passed by the magnetic head, the film may be accidentally curved as soon as the rough portion contacts the inside of the camera body. The flatness of the film is thus lowered, and accuracy in contact of the magnetic head with the recording layer is reduced. Commonly assigned Japanese Patent Publication JP-A 5-281605, discloses a magnetic head with a core which has curvature projected with reference to a longitudinal direction of the film and toward the film. This reduces influences of the roughly slitted portion on the magnetic recording process.
The pad which is swingable along the direction of feeding of the film, however, fails to absorb an inclination of the magnetic head in a direction along the width of the film, namely transverse to the feeding of the film. If the magnetic head is inclined significantly in the width direction of the film, the area of the contact between the magnetic head and the film is reduced and the performance in writing/reading data of the magnetic head is deteriorated.
A conventional pad for the magnetic head is produced from fabric, such as felt, and is provided with flexibility. When in cooperation with the magnetic head, the pad is pushed and depressed by the magnetic head while the magnetic head is pressed against the photo film. The pad, which remains pressed by the magnetic head during extended use of the camera, becomes deformed irrecoverably. The force for pressing the magnetic head against the photo film is thus lowered over time. If the magnetic head has a core which protrudes from the head, the pad may have a much greater size with reference to the film width direction than a size of the core. The center of the pad is thus remarkably deformed in an irrecoverable fashion. The output of the magnetic head while reading the data is considerably deteriorated, because the magnetic writing/reading device is degraded primarily at the center of the magnetic head.